Method of and apparatus for threading metal caps



'. 17, 1935. J. J. WILLIAMS METHOD OF AND APPARATUS FOR THREADING METAL CAPS Filed June 1, 1933 John J m'lliam' dl'l'onunyt- V Patented Dec. 17, 1935- UNITED STATES PATENT OFFICE.

METHOD OF AND APPARATUS FOR THREADING METAL GAPS Application June 1, 1933, Serial No. 673,921

12 Claims.

In the formation of screw-threaded closures for bottles, jars and the like, it is usual to provide an outturned bead or wire edge on the lower portion of the skirt, to conceal the raw edge of the metal and thus improve the appearance of the closure and also prevent injuries by contact of the hands with the sharp edge.

In rolling the threads in caps of this type it is highly desirable for the sake of economy to simultaneously roll the bead or wire edge. When caps have been thus prepared on conventional threading machines the depth of the threads formed was necessarily limited for the reason that the edge of the skirt was held fixed by the beading tool and hence the metal of the skirt'had to be stretched to form the threads.

It is old and well known to roll deep threads in metal caps, and machines for doing this are also old and well known, but in such machines it has been necessary to roll the bead or wire edge" before or after the formation of the threads.

One of the objects of the present invention is to provide a method and apparatus by which it is possible to roll deep threads in metal caps si-' mnltaneously with the rolling ofthe bead.

Another object of the invention is to provide a machine which will perform the operation of simultaneously rolling the bead and deep threads which requires very little change in the machines heretofore employed for simultaneously rolling the bead and shallow threads, thereby saving the expense of entirely new equipmnt.

Other objects and advantages of the invention -will be apparent to those skilled in the art, from the following detailed description when taken in connection with the accompanying drawing; in which,

Figure 1 is a sectional view of the tools partly in elevation, showing the initiation of the cap forming operation.

Figure 2 is a similar view showing the position of the tools at the conclusion of the cap forming operation.

Figure 3 is a sectional view through one of the hat-shaped blanks, and

Figure 4 is a view partly in elevation and partly v in section of. one of the completed caps.

Referring to the drawing in more detail the numerals l and 2 indicate a pair ofspindles which are mounted in the conventional manner for rotation and for relative movement toward provided with a projection I slid'ably mounted l a socket in the end of spindle l and'caused i rotate with the spindle by means of a key 8. bolt 9 passes through the center of tool 5 and it projection I and is threaded to spindle I. A hea II) on the bolt 9 limits the outward movemer of the curling tool 5 and its inward movement of course limited by engagement with the threat ing tool 3. A series of light springs ll mounted in pockets l2 in the outer face'of the thread- 10 ing tool serve to normally hold the curling tool at its outermost limit of movement; but it will be understood that various other devices may be employed for this purpose.

Fixedly secured to the spindle 2,are the male 1 knurling and threading tools l3 and I4, respectively, which cooperate with the similar tools on spindle l Tools l3 and I4 are pinned together as indicated by numeral l5, and a bolt l6 secures them against axial movement with respect to the 20 spindle 2. Slidably mounted on spindle 2, as by means of a key I1, is a curling tool 18 which cooperates with the curling tool 5 of spindle I. The c'urling tool I 8 is normally forced outward, i. e., away from its threading tool I, by means of 25 light springs l9 mounted in pockets I 9' in the threading tool. A shoulder 20 limits the outward movement of the curling tool, and of course its inward movement is limited by contact with its threading tool It. It will also be noted that the diameter of the curling tool 5 is preferably such as to cause its periphery to overlap that of the curling tool l8, for a purpose to be described.

A disc or table 2| provided with a stem 22 is rotatably mounted on a member 23. When the 35 disc 2| is moved forward it engages the top of the hat-shaped blank A (Figs. 1 and 3) when the latterisin place on the male chuck, and in conjunction with the chuck holds the blank in proper relation to the several tools. 40

When the hat-shaped blank is placed in position on the male chuck as just mentioned, the female chuck is caused to approach it, as shown in Figure 1. Of course both chucks are rotating, and the first part of the movement of one. chuck 45 toward the other starts the curling of the flange I of the blank; the parts being shown in Figure 1 as having reached this. position where the flange has just started to curl. As the female chuck continues its movement toward the male chuck, the threading tools immediately come into play to bend the skirt into the form of threads of any desired depth. And simultaneously with the formation of the threads the rolling of the head is completed. The knurling tools come into play at the same time, but the action of the knurling tools remains the same as heretofore, and no further description of the knurling is necessary.

As the bending of the metal proceeds in the 00 .flmnation of the threads the skirt of the blank begins to shrink and in so doing the edge of the skirt including the partly formed bead is drawn in the direction of the top of the blank. This movement is made possible by reason of the fact that the curling tools and I 8 which are gripping'the edge of the skirt are free to move axially of the spindles and hence can move with the bead as the skirt shrinks. The curling tools are drawn to the left from the position shown in Figure 1 until they finally reach a position approximating that shown in Figure 2 when the threads are completed. This movement of the curling tools with the bead is caused partly by the gripping action of the bead, partly by the fact that the bead is in' back of a part of the curved wall of the curling groove, and partly by reason of the overlapping of the peripheries of the two tools.

The freedom of movement of the edge of the skirt while the threads and bead are being formed admits of the formation of threads of any desired depth. it only being necessary that the skirt of the blank be of suflicient length to allow for the necessary shrinkage. Moreover, the performance of the several steps, namely, the knurling, the formation of the deep threads, and the curling of the bead, in a single operation provides a very material reduction in the time required in forming a flnishedcap and a consequent reduction in the cost of manufacture.

If the curling tools were fixed against axial movement, and an attempt was made to roll deep threads, the head would necessarily remain in a fixed position, and consequently the threads could be formed only by drawing or stretching the metal, and the stretching of the metal suihciently to form deep threads is liable to unduly weaken or rupture the metal. By allowing freedom of axial movement of the curling tools, the bead is allowed to move toward the top of the cap as the threads are rolled, and hence the metal is not unduly stretched but the skirt merely shrinks longitudinally as-the metal is forced into the threading grooves. It is thus apparent that by taking aoonventional threading mechanism, and modifying it to the extent of mounting the curling tools for longitudinal movement, I am able to roll deep threads simultaneously with the rolling of the bead, without in any way weakening or rupturing the metal of the cap. A completed cap is shown in Figures 2 and 4. and indicated by reference character B.

From the above description and the accom-v mngdrawingitwillbeapparenttothose skilled in theart that I have devised an improved method and apparatus for simultaneously formingdeepthread'sand abead'oncapblanks without danger of disrupting the metal and that the apparatus is extremely simple in construction movement of the bead toward the top of the cap while being formed.

2. The method of forming threads and a bead on a cap, which comprises simultaneously rolling the threads and the bead, and permitting the bead rolling means to travel toward the top of the cap as the bead is being formed.

3. The method of forming deep threads in the skirt of a cap and ahead on the lower edge thereof, which comprises simultaneously rolling 10 the threads and the bead and allowing relative bodily movement between the top of the cap and bead while the latter is being rolled.

4. The method of forming threads and a bead on a cap, which comprises simultaneously rolling a bead and threads and permitting the bead to shrink bodily with the skirt of the cap as the threads are formed in the skirt.

5. In an apparatus for simultaneously rolling threads and curling a head on cap blanks, a pair of relatively 'movable spindles, threading and curling tools carried thereby, said tools mounted for relative movement longitudinally of the spin dies to allow shrinking of the cap while the thread and bead are being formed.

6. In an apparatus for rolling threads and curling a head on cap blanks, including two relatively movable forming units, each unit including a spindle, threading and curling tools. and means for mounting the tools on the spindles to provide for relative movement longitudinally of the spindles between the threading and curling tools of each unit.

7. In an apparatus for simultaneously rolling i threads and curling a bead on cap blanks, a pair of relatively movable spindles, threading tools fixed to the spindles, and curling tools movable toward and from the threading tools. I

8. In an apparatus for rolling threads and curling a head on cap blanks,-a pair of relatively movable spindles, threading tools fixed to the spindles, and curling tools slidably mounted on the spindles and adapted to move toward and y from the threading tools.

to be included within the scope of the appended v claims What I-claim is:

1. The method of forming threads and a bead on a cap. which comprisa simultaneously rolling thethrecdsand thebeadand permittingbodily 9. In an apparatus for rolling threads and curling a bead on can blanks, a pair of spindles, cooperating threading tools carried by the spindles, acurling tool slidably mounted on each spindle, and means for normally holding each curling tool spaced from the adJacent threading tool.

10. In an apparatus for simultaneously rolling threads and curling ahead on cap blanks. a pair of spindles, cooperating threading tools carried by the spindles, a curling tool keyed to each spindie, and resilient means for normally holding each curling tool spaced from the adjacent threading tool. r

11. In an apparatus for simultaneously rolling threads and curling a of spindles, cooperating threading tools by the spindles, a curling tool keyed to each spindle, and springs interposed between each threading tool. and the adjacent curling tool.

12. In an apparatus for simultaneously rolling threads and curling a head on cap blanks, a pair of spindles, cooperating .tools carried by the spindles, and a curling tool keyed to each spindle and slidable thereon, the peripheries of the curling tools being in overlapping relation.

JOHN J. W.

carried- 

